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mirror image - ensemble II HF
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question : Are there any components that can be burned out or degraded by RFI that would affect the quadrature output?
background-- I built this ensemble II years ago and it's has worked perfectly in the radio shack. A year or two ago it seems to have developed a mirror image problem including on a not so new Win10 I3 machine that used to work fine with it that I still use. It shows mirror images on my macbook, a win10 laptop, another Win10 workstation, or a new Win11 desktop. Realizing that some new computers and my own in particular, do not support a stereo mic input and/or are extremely vague in their techinical spec for the internal sound cards, I tried several USB cards, the latest, a Behringer UCA202 USB unit that definitely supports stereo inputs. No joy on any computer. All that circumstantially isolates the problem to the Ensemble II itself. The ensemble II still receives and tunes fine but I cannot eliminate the mirror image on the display. Both left and right outputs work. (one alone would produce a mirror image). But combined, the quad phase difference should remove the mirror image. Finally - before giving up, I consulted (I probably used that doc to assemble it - the websites have changed in that time ... ) ... checked voltages, etc. I inspected the traces with magnification for shorts, found nothing, but reflowed anything suspicious. I don't have a scope which would probably nail the problem down. Q: what next? Q: which components can malfunction (.e.g. burned out or degraded by RFI ) and affect the quadrature output? thanks all, Peter KH6DK |
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On 21/02/2023 03:10, Peter Matsunaga wrote:
Both left and right outputs work.Peter, I only remember the two being shorted to have been the reason for no IQ cancelling with both signals present. Maybe cable, socket, JP2 jumpers. Possible failures:- Dry joint on T5 secondary. R53, 54. Check voltages/joints on U10, U11. 73 Alan G4ZFQ |
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Hello Peter,
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You can use an audio recording software like audacity Record two channels with a frequency selected that gives you a single dominating station - or use a signal generator. Then expand the time scale so you can see the sinewaves and their amplitude and phase relation. 73 Leif question : Are there any components that can be burned out or degraded by RFI that would affect the quadrature output? |
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Warren, what you said struck a note - something like this happened when I
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was testing a few days ago but I didn't chase it down. It is an easy test with this Behringer soundcard which uses rca jacks for line input right and line input left from the softrock. The cable has 3mm stereo jack plugged into softrock output. The other end of the cable has rca plug right and rca plug left. softrock tuned to 10mhz so I have wwvh test signal. Tried it. { out on an errand. Back again. } Here's what happened. Either softrock channel plugged into the left input of the USB soundcard 'works' but input to the right channel produces no signal for the HDSDR program. Either L or R softrock output channel produces a signal ( with mirror images) in HDSDR when plugged into the Left channel of the USB audio as might be expected. So there is a problem on the Right channel on the Behringer. ( i need to find some other signal to inject on that input to double check too.) Doesn't rule out a windows driver issue either (and that's a way down the rabbit hole). And still not sure about the IQ, but a stereo input issue is back to #1 suspect so gotta chase that down. My other USB audio device ( Sabent - used for FT8 on my macbook ) uses 3mm stereo plugs input. questionable spec. ..it produces the mirror image too.. I'd need to make a 3mm stereo breakout to try the L/R swap on it. jeez- lack of stereo - is back on top of the suspect list - for sure I'm not getting rid of the mirror image until I solve that. thanks for the suggestion Warren. If we get stereo back and I still have a problem then we'll go back to the PCB of the softrock and check out Alan's suggestion. thanks for the help - P On Thu, Feb 23, 2023, 4:28 AM Warren Allgyer <allgyer@...> wrote:
Peter |
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Peter,
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Most recently I had this problem due to the cable from RX II to my sound cards. In one case it was the jack to split from cable with stereo plug to 2 lines for usb sound cards like Behringer-202. Some time ago it was due to a dead channel on a Behringer-202. Once it was the opamp chip in the RX II. Once on a just-built one it was something on the 7474 chip- either chip or solder. Regards K0IMH On Feb 25, 2023, at 8:30 PM, Peter Matsunaga <petermatsun@...> wrote: |
Warren Allgyer
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